cruise control stops functioning

It could be several things. it is best to have your Cruise Control scanned and then see what the real problem is. Modern vehicles have the Cruise Control built into the Power Train Computer. There are many factors. When you scan the Cruise Control, you start with verifying the CC switch and then all the input sensors. Do your Brake Lights work properly, that ( the brake light switch ) too is an important input. Best of Luck!